Diesel Fault Code Library
Workshop-grade guides for 121 diesel diagnostic trouble codes — what each code means, injector-related and other causes, how mechanics diagnose it, and realistic UK repair costs.
121 fault code guides
5 fault categories
Injector Circuit Faults(37)
P0200Injector Circuit / OpenP0201Injector Circuit Malfunction (Cylinder 1)P0202Injector Circuit Malfunction (Cylinder 2)P0203Injector Circuit Malfunction (Cylinder 3)P0204Injector Circuit Malfunction (Cylinder 4)P0261Injector Circuit Low (Cylinder 1)P0262Injector Circuit High (Cylinder 1)P0264Injector Circuit Low (Cylinder 2)P0265Injector Circuit High (Cylinder 2)P0267Injector Circuit Low (Cylinder 3)P0268Injector Circuit High (Cylinder 3)P0270Injector Circuit Low (Cylinder 4)P0271Injector Circuit High (Cylinder 4)P0273Injector Circuit Low (Cylinder 5)P0274Injector Circuit High (Cylinder 5)P0276Injector Circuit Low (Cylinder 6)P0277Injector Circuit High (Cylinder 6)P0279Injector Circuit low (Cylinder 7)P0280Injector Circuit high (Cylinder 7)P0282Injector Circuit low (Cylinder 8)P0283Injector Circuit high (Cylinder 8)P0611Fuel Injector Control Module PerformanceP062BECM Fuel Injector Control PerformanceP1201Injector Circuit Fault (Cylinder 1)P1202Injector Circuit Fault (Cylinder 2)P1203Injector Circuit Fault (Cylinder 3)P2146Injector Group A Supply VoltageP2149Fuel Injector Group B Supply Voltage Circuit/OpenP2150Fuel Injector Group B Supply Voltage LowP2151Fuel Injector Group B Supply Voltage HighP2152Fuel Injector Group C Supply VoltageP2153Fuel Injector Group C Supply Voltage LowP2154Fuel Injector Group C Supply Voltage HighP2155Fuel Injector Group D Supply VoltageP2156Fuel Injector Group D Supply Voltage lowP2157Fuel Injector Group D Supply Voltage highP2292Injector Control Pressure Erratic
Cylinder Contribution & Balance(7)
Cylinder Misfires(9)
Fuel Rail & Pressure(26)
P0087Fuel Rail/System Pressure Too LowP0088Fuel Rail/System Pressure Too HighP0089Fuel Pressure Regulator PerformanceP008ALow Pressure Fuel System Pressure Too LowP008BLow Pressure Fuel System Pressure Too HighP0090Fuel Pressure Regulator 1 Control CircuitP0091Fuel Pressure Regulator 1 Control Circuit LowP0092Fuel Pressure Regulator 1 Control Circuit HighP0093Fuel System Large Leak DetectedP0094Fuel System Leak DetectedP0190Fuel Rail Pressure Sensor A CircuitP0192Fuel Rail Pressure Sensor A Circuit LowP0193Fuel Rail Pressure Sensor A Circuit HighP0194Fuel Rail Pressure Sensor Circuit IntermittentP228CFuel Pressure Regulator ControlP228DFuel Pressure Regulator PerformanceP2290Injection Control Pressure Too LowP2293Fuel Pressure Regulator 2 PerformanceP2294Fuel Pressure Regulator 2 Control CircuitP2295Fuel Pressure Regulator 2 Control Circuit LowP2296Fuel Pressure Regulator 2 Control Circuit HighP2539Low Pressure Fuel System Sensor Circuit / OpenP2540Low Pressure Fuel System Sensor Range/PerformanceP2541Low Pressure Fuel System Sensor Circuit LowP2542Low Pressure Fuel System Sensor Circuit HighP2543Low Pressure Fuel System Sensor Circuit Intermittent
Fuel Pump, Metering & Control(42)
P0001Fuel Volume Regulator Control Circuit / OpenP0002Fuel Volume Regulator Control Circuit Range/PerformanceP0003Fuel Volume Regulator Control Circuit LowP0004Fuel Volume Regulator Control Circuit HighP0148Fuel Delivery ErrorP0149Fuel Timing ErrorP0168Fuel Temperature Too HighP0170Fuel Trim Malfunction (Bank 1)P0171System Too Lean (Bank 1)P0172System Too Rich (Bank 1)P0173Fuel Trim Malfunction (Bank 2)P0174System Too Lean (Bank 2)P0175System Too Rich (Bank 2)P0180Fuel Temperature Sensor A CircuitP0181Fuel Temperature Sensor A Range/PerformanceP0182Fuel Temperature Sensor A Circuit LowP0183Fuel Temperature Sensor A Circuit HighP0184Fuel Temperature Sensor A Circuit IntermittentP0185Fuel Temperature Sensor B CircuitP0186Fuel Temperature Sensor B Range/PerformanceP0187Fuel Temperature Sensor B Circuit LowP0188Fuel Temperature Sensor B Circuit HighP0216Injection Timing Control CircuitP0230Fuel Pump Primary CircuitP0231Fuel Pump Secondary Circuit LowP0232Fuel Pump Secondary Circuit HighP0251Injection Pump Fuel Metering Control AP0252Injection Pump Fuel Metering Control A Range/PerformanceP0253Injection Pump Fuel Metering Control A LowP0254Injection Pump Fuel Metering Control A HighP0255Injection Pump Fuel Metering Control B Range/PerformanceP0256Injection Pump Fuel Metering Control BP0257Injection Pump Metering Control B LowP0258Injection Pump Metering Control B HighP025AFuel Pump Module Control CircuitP025BFuel Pump Module Control Range/PerformanceP025CFuel Pump Module Control Circuit LowP025DFuel Pump Module Control Circuit HighP0627Fuel Pump A Control Circuit OpenP0628Fuel Pump A Control Circuit LowP0629Fuel Pump A Control Circuit HighP2635Fuel Pump A Low Flow / Performance
Injector Problems & Symptoms
Diagnose by symptom — knocking, smoke, misfires
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Injector guides by engine code
Knowledge Centre — Fault Codes
Workshop-depth fault code explainers
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Frequently asked questions
Are these fault codes diesel-specific?
The codes are standard SAE J2012 / OBD-II definitions, but every guide here is written for diesel common-rail systems — injector-related causes, leak-off testing, rail pressure diagnosis and realistic UK repair costs.
Does a fault code always mean a failed injector?
No. Each guide separates injector-related causes from wiring, sensor, pump and ECU causes, and explains how mechanics isolate the true fault before replacing parts.
My code isn't listed — can you still help?
Yes. The library expands continuously and our diesel specialists can help diagnose any injector-related code. Call 020 3355 6581 or use the part-number search to find your replacement injector.